Except jobs can't be just reinstated when people are out of them so long that the knowledge moves elsewhere or experiments expire. Irreparable harm also includes things like injury to reputation, goodwill, professional practice.

The impending harm here is explicit, immediate, and as demonstrated previously serious for these labs and research fields. It's unfortunate that Judge Cobb didn't find this to be sufficient, but hopefully on appeals some relief may be offered.

Temporary loss of income is I think not generally a basis for irreparable harm for more or less the argument you hint at.